BA10/NP207 To AX15/NP231 Swap Help - Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > YJ Jeep Wrangler Forum > YJ Tech Forum

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 04-14-2014, 08:57 PM   #1
Jeeper
 
Brandon D's Avatar
 
Join Date: Feb 2014
Posts: 30
BA10/NP207 To AX15/NP231 Swap Help

Background: I have an '87 with the 4.2l I6/NP207 combo and I'm wanting to swap it for an AX15/NP231 combo.

1) What year AX15 (if there's any specific) will I need to get that will bolt to the '87 4.2?
2) Will I need to change the pilot bearing? If so, which one?
3) Will I need to change the clutch or flywheel? If so, which one?
4) Will I need to change the starter? If so, which one?
5) Will I need new mounts for the AX15/NP231?
6) Am I forgetting anything?

Thanks!

Brandon D is offline   Quote
Old 04-14-2014, 09:35 PM   #2
Jeeper
 
Jeeprich25's Avatar
 
Join Date: Sep 2010
Posts: 831
You should try going on autozone, searching for those parts for your year, and later. Then maybe seeing I they're the same. There's your answer.

__________________
1990 Jeep Wrangler YJ. 2.5L. Bone Stock, mostly.

"I'd have more money for upgrades if it didn't break every week."
Jeeprich25 is offline   Quote
Old 04-14-2014, 10:00 PM   #3
Jeeper
 
Brandon D's Avatar
 
Join Date: Feb 2014
Posts: 30
Well I figured someone on here may have already done the swap and would be able to help me out.

I'll give it a shot.
Brandon D is offline   Quote
Old 04-14-2014, 10:26 PM   #4
Jeeper
 
Beachcruiser's Avatar
 
Join Date: Feb 2012
Location: Raleigh, NC
Posts: 429
There's a couple of fantastic write-ups on this swap if you google it.

Basically, using the 4.2 flywheel & clutch for your year 4.2:

a 90-91 donor is a virtual bolt in using the 4.2 clutch, ax-15, bellhousing & attached Tcase. Pilot is the same (tho I replaced mine along w/ clutch), only have to drill new holes in skid plate to mount the trans (AX-15 mount). Even the speedo cable works fine.

Later versions of the AX-15 w/ big pilotshaft tip need a new pilot bushing (from CJ w/ 304) & may have a different speedo drive depending on year. If they are a 94-up, then they will need a different hydraulic line for the external slave cylinder too.

The starter remains the same.

It helps immensely to get the whole shebang from bellhousing to Tcase (including shifters/linkage!) from one donor. My 91 donor bolted right up, driveshafts & all.
Beachcruiser is offline   Quote
Old 04-14-2014, 10:42 PM   #5
Jeeper
 
Brandon D's Avatar
 
Join Date: Feb 2014
Posts: 30
THANK YOU! This is exactly what I needed!

Was it a 90-91 YJ you used for the donor?
Brandon D is offline   Quote
Old 04-15-2014, 08:20 AM   #6
Jeeper
 
Beachcruiser's Avatar
 
Join Date: Feb 2012
Location: Raleigh, NC
Posts: 429
You're welcome....Yes, my donor was a 91 YJ.

I replaced the clutch since I was in there at the time, as well as the slave cylinder w/ the best I could find. No problems in 2+ years of wheeling since then.
Beachcruiser is offline   Quote
Old 04-15-2014, 12:43 PM   #7
Jeeper
 
StanF's Avatar
 
Join Date: Jan 2013
Location: Austin, TX
Posts: 1,102
If you are going to do this, then you'll definitely want the external slave for the AX15. 1994 and up will have this.

So either:

1) early AX15 for the input shaft diameter, but later AX15 bell housing, etc.

2) just get a later AX15 and deal with the special pilot bearing (my recommendation). You'll find a bunch more of them. And since they are newer, they will likely have fewer miles on them.
.
.
__________________
1995 YJ, 4.0L, AX15, 3" susp lift; Lock Right in Dana 30; 8.8 w/ARB; Flat Tummy Tuck, 1" Daystar BL; 1" MORE MML; 35" MT/r Tires;

StanF Tummy Tuck, Ford 8.8, Gas Tank Lift, Rocker Guard Fab, Ammo Can Console
StanF is offline   Quote
Old 04-15-2014, 02:43 PM   #8
Jeeper
 
Brandon D's Avatar
 
Join Date: Feb 2014
Posts: 30
What are the pro's and con's of an external slave cylinder?
Brandon D is offline   Quote
Old 04-15-2014, 04:41 PM   #9
Jeeper
 
StanF's Avatar
 
Join Date: Jan 2013
Location: Austin, TX
Posts: 1,102
Quote:
Originally Posted by Brandon D View Post
What are the pro's and con's of an external slave cylinder?
There are no cons

The internal slave is a weak point, and you have to pull the transmission to fix it. It's an awesome thing to have
__________________
1995 YJ, 4.0L, AX15, 3" susp lift; Lock Right in Dana 30; 8.8 w/ARB; Flat Tummy Tuck, 1" Daystar BL; 1" MORE MML; 35" MT/r Tires;

StanF Tummy Tuck, Ford 8.8, Gas Tank Lift, Rocker Guard Fab, Ammo Can Console
StanF is offline   Quote
Old 05-26-2015, 06:40 PM   #10
Newb
 
Join Date: May 2015
Posts: 2
4.2 conversion to 92+ AX-15 (with larger input shaft) uses pilot bearing # PB-77HD (Oreileys) or one from Novak.
SaltWaterRednek is offline   Quote
Old 06-07-2015, 12:03 PM   #11
Newb
 
Join Date: Sep 2013
Location: Lafayette, Colorado
Posts: 3
Chiming in here - I am currently doing this swap, I have a 1989 YJ 4.2 and went with a used AX15 out of a 93 YJ with internal slave for cost, I used the larger pilot bearing that fits the outside hole on the since the 93 had the larger input shaft. I used the stock Master from the 89 (npt fitting) and purchased the internal Slave for the 93 which had the push style so I cut it off, and plumbed in the brass fitting. OK, HERE IS WHERE I NEED SOME HELP!! Everthing fell into place pretty smoothly and got it all mounted up, bled the system and seems like I have Clutch, BUT Now the entire drivetrain seems locked up - Even though it shifts smoothly into all gears and neutral, it will not roll at all and I can't get it to turnover either. Soooo, looking for any possible ideas before I start ripping it all back out again.. (By the way, once i found the Transmission bracket, the original skid plade was used and the holes lined right up as did the muffler to the bracket on the mount-like I said everthing went together smoothly and thought life was good again ///// NOT)
Bad Tranny?

ssleppy is offline   Quote
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Download our Mobile App

» Featured Product

All times are GMT -5. The time now is 03:49 AM.


User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.

Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC